Background & Objective: Dependence on substance or addiction is a psychological disturbance. This is referred to as substance abuse in psychological classifications and is the second most common psychological disturbance. On the other hand depression is an instance of disturbance, which is observed among the victims of substance abuse. This study set out to evaluate the effectiveness of Cognitive-Behavior Therapy (CBT) of depression among patients with substance abuse.

 Methods: Using experimental method, 28 men and women (23-35 years, normal IQ) with substance abuse were randomly selected according to DSMIV criteria. These subjects had been under anti-addiction medication for two years, without adequate control, and were divided into two groups. The two groups received the following treatments for 6 weeks: 1- Cognitive Behavior Therapy. 2- No specific psychological treatment (control group). Two instruments were used to collect data namely Beck Depression Inventory (BDI) to evaluate depression and demographic forms to record the information.

 Results: The data were analyzed using repeated measurements including a pretest and two posttests. In pretest, according to scores of both groups from Beck test, there was a severe depression among the subjects. However in the second and third posttests these scores fell significantly. The intra-group and inter-group tests showed that these reduction in scores was related to the intra-group differences.

 Conclusions: CBT has had an important role in treatment of depression among patients with substance abuse. Psychological intervention was able to help them change their cognition by decreasing depression and enable them to have a more positive belief in controlling themselves against dependency. It seems that taking psychologically team-approach (both theoretically and practically) about control strategies and treatment of depression in patients with substance abuse can deeply improve their life style as well as their individual and social relations.